Transmission and conveyor belt



Dec. 9, 1947. H. M. KUHN 2,432,427

TRANSMISSION ND CONVEYOR BELT l Filed Feb. 24, 1944 ATTORNEY Patented Dec. 9, 1947 I uNiTsD `STATES 4PATENTV OFFICE TRANSMISSION AND CONVEYOR BELT Herbert M. Kuhn, Clifton, N. J., assignor to United States Rubber Company, New York, N. Y., a corporation of New Jersey Application February 24, 1944,` Serial No. 523,768

This invention relates to laminated belts formed of two, or more sheets of woven fabric bonded x zcxaims. (c1. vii- 232) mission belts or conveyor belts the plies of rein- K forcing fabric are increased as necessary to supply the required strength, but this'` increase in the number .ofplies increases the weight and stiffness of the belt, with the result that an additional amount of power is required to drive the heavier belt and to bend such belt around the pulleys.

It has been attempted heretofore tokeep down the weight of such heavy duty belts by employing woven sheets of rayon as the reinforcing material in place of woven sheets of cotton, but in laminated belts it is extremely important that the reinforcing sheets be firmly bonded together so that these sheets will not separate under the various forces to which the belt may be subjected in use. lIf ply separation occurs the belt must be discarded. These attempts heretofore to use rayon fabric as the reinforcing plies in transmission and conveyor belts have not proved satisfactory because rubber and rubber-like materials do not bond well to rayon, and much difficulty has been experienced in securing a satisfactory bond between the rayon ply sheets. It has also been diillcult to impregnate such rayon fabric satisfactorily with rubberor rubber-like material, or satisfactorily friction the surface of the fabric with these materials.

Having in mind the foregoing, the present invention contemplates a construction whereby laminated belts may be provided with the strength and other advantages contemplated by the use of rayon reinforcing plies, but the difficulty experienced heretofore in securing-a. rm adhesive bond between the plies of rayon fabric is-over come.

The primary feature of the present invention resides in a laminated belt employing in its construction two or more woven reinforcing sheets, each of which sheets has rayon or other strong threads to which rubber does not bond well extending in one direction, and cotton threads to which rubber bonds readily extending at right angles to such strong threads in the woven fabric.

In most cases lin using such reinforcing fabric in a belt itwill beI desirable 'to arrange the rayon or other strong threads so that they extend lengthwise of the belt and the cotton threads to extend transversely of the belt. In such a construction the rubber or other bonding mate'- rial will adherermly to the cotton threads but poorly to the rayon threads with the result that evenly distributed weak and strong lbonding points will be formed between the sheets of fabric throughout the adhesive-area.. That is the rubber will adhere firmly to the cotton where-it is exposed between the rayon threads.'

strength lengthwise of the belt where it is needed -to prevent the belt from breaking or elongating appreciably, and also provides a novel type of bond between the fabric sheets that holds them rmly together, but permits a high degree of flexibility. IThat is since the rubber is bonded firmly to one st of threads but not to the other set the present belt will have greater flexibility than a similar belt in which the rubber is bonded rmly to both the warp and weft threads. 1

The above and other features of the present invention and advantages resulting from the present construction will be more fully understood from the following description when read in connection with the accompanying drawing wherein:

Fig. l is a plan viewv of a short piece of belt constructed in accordance with the present invention.

Fig. 2 is a section taken on the line 2--2 of Fig. 1;

Fig. 3 is a view similar to Fig. 2 but on a much larger scale. Y

Fig. 4'is a view similar to Fig. 3 except that the two fabric sheets are shown as pulled away from each other slightly to stretch the rubber bonding layer therebetween; and

Fig. 5 is the same type of view as Fig. 4 except that the section of Fig. 4 is taken parallel to the cotton threads whereas the section of Fig. 5 is taken parallel to the rayon threads.

A transmission or conveyor belt constructed in accordance with the present invention may embody two or more plies of reinforcing fabric, de-

pending upon the strength it is desired to impart sheet I l.

prise a square Woven sheet of duck having cotton threads to which rubberv bonds Well extending in one direction of the fabric, and stronger threads such as'rayon, nylon, silk or glass to which rubber does not adhere readily extending at right angles to the cotton threads. In the preferred construction each reinforcing sheet I and II Will be formed of cotton weft threads I3 extending transversely of the belt and rayon or other strong Warp threads I4 extending longitudinally of the belt where they will serve yto withstand the strong longitudinal pull exerted upon a transmission belt when driving a heavily loaded pulley, or exerted upon a conveyor belt when operating as a long or heavily loaded conveyor. The outer faces of the belt may be free of rubber, or provided with a protecting layer of rubber which is frictioned or otherwise applied to the fabric as desired depending largely upon the type 0f use for which the belt is designed. That is whether or not the cuter face of the belt is likely to be subjected to -severe wear.` The fabric sheets I0 and II may be formed of,various combinations of the cotton threads I3 and the stronger threads I4 other than that shown, and, if desired, both types of vthreads may be woven in parallel relation to each other in vthe warp or weft, or in both the warp and weft.

The important construction of any ply belt is the bond lbetween the plies which must be strong enough to hold the reinforcing plies together when the belt operates at maximum speed or pulling force, whileat the same time the bond must be sufficiently flexible to accommodate the bending of the belt as it passes around the pulleys.

After the sheets of fabric III and II and the desired amount of unvulcanized rubber or other flexible bonding material lI2 have been brought together in the form of a sandwich the belt thus formed may be vulcanized in the usual press as heretofore. These vulcanizing presses usually are operated under high pressure so that the unvulcanized rubber I2 will be forced into the fabric about the exposed portions of both the cotton and rayon threads, so that if a section is taken through the belt after vulcanization as in Fig. 3 the rubber may appear to be well attached to the rayon threads I4 as well as to the cotton threads I3.

If, however, the fabric sheets I0 and Il are forced away from each other a short distance while maintained in parallel'relation to each other, as shown in Figs. 4 and 5 it will be noted that the tension` thus exerted on the bonding sheet I2 will cause the rubber to sag away from the rayon threads asindicated by :l: while it will remain firmly bonded to the cotton threads as indicated by y.

In the present construction the rubber bonding material I2 will so adhere to the reinforcing sheets I0 and II that evenly distributed weak and strong bonding points'will be formed `over each face of the rubber sheet. The effect of this will be to provide gr-eater freedom of movement between the parts of the belt, as the belt bends around a pulley or assumes the shape of a trough to convey a load, than in the belts usedr heretofore where the entire fabric surface was adhered firmly to the rubber sheet.

In actual practice it has been found that a belt constructed in accordance with the present invention is much stronger than a belt having the same number and weight of plies but formed entirely of cotton, and the present belt has better flexing properties than a similar belt reinforced entirely of cotton. This increased flexibility of the .present belt is believed to be due largely to the above described construction whereby the rubber is bonded strongly to the cotton threads where they appear at the face of the fabric but less strongly to the rayon threads.

As a result of the present invention a belt is provided which is much stronger than the cotton belts of the same'weightemployed heretofore, and the present belt is found to have excellent wearing properties and adhesion between the plies, and very good flexing properties. A three ply belt construction in accordance with the present invention may be used in place of a four ply belt formed entirely of cotton, the weight of a single ply being the same in each construction. This reduction in the weight of the belt makes possible a corresponding' saving in the power required to drive the belt.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A strong and highly flexible laminated belt formed of woven sheets of fabric bonded together by an elastic adhesive material, each woven sheet being formed of cotton threads to which the bonding material adheres firmly and rayon threads interwoven. with the cotton threads and to which the bonding material adheres poorly, whereby evenly distributed weak and strong bonding points between the woven sheets and adhesive are formed throughout the adhesive area and a belt is-produced of greater strength and flexibility than a belt having the same construction except that the woven sheets are formed entirely of cotton.

2. A strong and highly flexible laminated belt formed of woven sheets of fabric bonded together by an elastic adihesive material, each Woven sheet being formed of cotton threads to which the bonding material adheres firmly and strong artificial textile threads interwoven with the cotton threads and to which the bonding material adheres poorly, whereby evenly distributed weak and strong bonding points between the Woven sheets and adhesive are formed throughout the adhesive area and a ybelt is produced of greater strength and flexibility than a belt having the same construction except that the woven sheets are formed entirely of cotton.

HERBERT M. KUHN.

REFERENCES CITED The following references are of record in the nle of this patent:

UNITED STATES PATENTS Number Name Date 2,179,655 Cutler Nov. 14,1939 66,111 White et al June 25, 1867 2,107,013 Morgan Feb. l, 1938 2,064,781 Collins Dec. 15, 1936 2,008,353 Geare July 16, 1935 FOREIGN PATENTS Number Country Date 6,106 Austria Aug. 1, 1901 482,774 Great Britain Apr. 5, 1938 

